Street Fight Daily: Foursquare’s 20M, Groupon Acquires Ditto.me

A roundup of today’s big stories in hyperlocal content, commerce and technology...

Foursquare Hits 20M Users — But How Many Are Active? (ReadWriteWeb)…

Groupon Acquires Social Recommendation App Ditto.me (TechCrunch)…

Former Yahoo Exec: 30% of PC Search Is Local (ScreenWerk)…